Improving pilling resistance in fabrics using cellulose acetate staple fibers

ABSTRACT

A method of making a pilling-resistant fabric is provided. In one instance, the method comprises (a) blending a cellulose acetate (CA) staple fiber with a non-CA staple fiber to form a blended yarn comprising 20 to 80 wt % of the CA staple fiber and (b) forming a pilling-resistant fabric comprising the blended yarn. In another instance, the method comprises (a) providing a first yarn comprising at least 20 wt % of a CA staple fiber and (b) forming a pilling-resistant fabric comprising the first yarn and a second yarn comprising a non-CA staple fiber. The CA staple fiber has (i) a round or closed-C cross-sectional shape, (ii) a cut length of 20 to 80 mm, (iii) a crimp frequency of 4 to 24 crimps per inch (CPI), and (iv) a denier per filament (DPF) of 0.5 to 4.0. The pilling-resistant fabric has a higher pilling resistance rating than a fabric made without the CA staple fiber.

TECHNICAL FIELD

The invention generally relates to the field of fabrics or textiles. In particular, it relates to fabrics or textiles having improved pilling resistance.

BACKGROUND

One of the key fabric properties for a variety of textile applications is pilling on the surface of the fabrics upon use. Pilling refers to the formation of loose balls or fuzz on the surface of the fabric. The pilling process starts when the fabric undergoes repeated rubbing, washing, and/or abrading. These actions cause small loose fibers to protrude from the surface of the fabric. Over time, the protruding fibers develop into small spherical bundles, which are attached to the surface of the fabric by other protruding fibers that have not broken off. This fuzziness creates a non-uniform and less appealing fabric appearance for the garment.

Many fabrics, regardless of the type of fiber from which they are made, have a tendency to pill, to some extent.

Thus, there is a need in the art to provide fabrics that have improved pilling resistance.

The present invention addresses this need as well as others, which will become apparent from the following description and the appended claims.

SUMMARY

The invention is as set forth in the appended claims.

Briefly, in one aspect, the invention provides a method of making a pilling-resistant fabric. In some instances, the method comprises:

(a) blending a cellulose acetate (CA) staple fiber with a non-CA staple fiber to form a blended yarn comprising 20 to 80 wt % of the CA staple fiber, based on the total weight of the blended yarn; and

(b) forming a pilling-resistant fabric comprising the blended yarn.

In other instances, the method comprises:

(a) providing a first yarn comprising at least 20 wt % of a cellulose acetate (CA) staple fiber, based on the total weight of the first yarn; and

(b) forming a pilling-resistant fabric comprising the first yarn and a second yarn comprising a non-CA staple fiber.

In another aspect, the invention provides a blended yarn comprising:

(a) 20 to 80 wt % of a cellulose acetate (CA) staple fiber, based on the total weight of the blended yarn; and

(b) a non-CA staple fiber,

wherein a fabric made from the blended yard has a higher pilling resistance rating than a fabric made without the CA staple fiber.

In yet another aspect, the invention provides a pilling-resistant fabric which comprises the blended yarn.

In yet another aspect, the invention provides a pilling-resistance fabric comprising:

(a) a first yarn comprising at least 20 wt % of a cellulose acetate (CA) staple fiber, based on the total weight of the first yarn; and

(b) a second yarn comprising a non-CA staple fiber.

The CA staple fiber can be characterized by:

(i) a round or closed-C cross-sectional shape;

(ii) a cut length of 20 to 80 mm;

(iii) a crimp frequency of 4 to 24 crimps per inch (CPI); and

(iv) a denier per filament (DPF) of 0.5 to 4.0.

The pilling-resistant fabric has a higher pilling resistance rating than a fabric made without the CA staple fiber.

In yet another aspect, the invention provides an article of manufacture comprising the pilling-resistant fabric. The article comprises a garment, a window or seat covering, or bedding.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE shows the different parameters used for determining the crimp amplitude of a crimped fiber.

DETAILED DESCRIPTION

It has been surprisingly found that blending certain cellulose acetate (CA) staple fibers with non-CA staple fibers can produce fabrics with improved pilling resistance ratings compared to fabrics made 100% of the non-CA staple fibers, such as viscose, lyocell, modal, etc. Fabrics made with the CA staple fibers can show improved pilling results using standard AATCC & ISO test methods.

Without wishing to be bound by theory, fabrics made with the CA staple fibers can reduce the ability of pills to form and/or to anchor themselves in order to break the cycle of pill formation on the fabrics. As the total pill cycle time (from formation to detachment) can be shorter in fabrics made with the CA staple fibers, the fuzz or short balls, if any, on the fabric surface remain short lived. This creates a more uniform fabric surface for a longer period of time over repeated use and wash cycles.

Thus, in one aspect, the invention provides a method of making a pilling-resistant fabric.

In some instances, the method comprises the steps of:

(a) blending a cellulose acetate (CA) staple fiber with a non-CA staple fiber to form a blended yarn comprising 20 to 80 wt % of the CA staple fiber, based on the total weight of the blended yarn; and

(b) forming a pilling-resistant fabric comprising the blended yarn.

A “staple fiber” refers to a fiber cut from a continuous filament or tow band of continuous filaments.

In a related aspect, the invention provides a blended yarn comprising:

(a) 20 to 80 wt % of a cellulose acetate (CA) staple fiber, based on the total weight of the blended yarn; and

(b) a non-CA staple fiber,

wherein a fabric made from the blended yard has a higher pilling resistance rating than a fabric made without the CA staple fiber.

The blended yarn may comprise from 20 to 75 wt %, 20 to 70 wt %, 20 to 65 wt %, 20 to 60 wt %, 20 to 55 wt %, 20 to 50 wt %, 20 to 45 wt %, 20 to 40 wt %, 25 to 80 wt %, 25 to 75 wt %, 25 to 70 wt %, 25 to 65 wt %, 25 to 60 wt %, 25 to 55 wt %, 25 to 50 wt %, 25 to 45 wt %, 25 to 40 wt %, 30 to 80 wt %, 30 to 75 wt %, 30 to 70 wt %, 30 to 65 wt %, 30 to 60 wt %, 30 to 55 wt %, 30 to 50 wt %, 30 to 45 wt %, 30 to 40 wt %, 35 to 80 wt %, 35 to 75 wt %, 35 to 70 wt %, 35 to 65 wt %, 35 to 60 wt %, 35 to 55 wt %, 35 to 50 wt %, 35 to 45 wt %, or 35 to 40 wt % of the CA staple fiber.

The balance of the blended yarn comprises one or more non-CA staple fibers. Examples of non-CA staple fibers include nylon, wool, silk, acrylic, bamboo, linen, hemp, cotton, lyocell, modal, polyester, viscose, and spandex. Combinations of these fibers may be used. In some instances, the non-CA staple fiber comprises cotton, lyocell, modal, polyester, viscose, spandex, or combinations thereof.

In yet another related aspect, the invention provides a pilling-resistant fabric which comprises the blended yarn.

The pilling-resistant fabric may comprise at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, or 100 wt % of the blended yarn.

In the case that the pilling resistant fabric comprises less than 100 wt % of the blended yarn, the balance of the fabric may comprise yarn made from one or more of the non-CA staple fibers.

In other instances, the method of making a pilling-resistant fabric comprises the steps of:

(a) providing a first yarn comprising at least 20 wt % of a cellulose acetate (CA) staple fiber, based on the total weight of the first yarn; and

(b) forming a pilling-resistant fabric comprising the first yarn and a second yarn comprising a non-CA staple fiber.

In a related aspect, the invention provides a pilling-resistance fabric comprising:

(a) a first yarn comprising at least 20 wt % of a cellulose acetate (CA) staple fiber, based on the total weight of the first yarn; and

(b) a second yarn comprising a non-CA staple fiber.

The first yarn may comprise up to 100 wt % of the CA staple fiber. For example, the first yarn may comprise from 20 to 100 wt %, 20 to 95 wt %, 20 to 90 wt %, 20 to 85 wt %, 20 to 80 wt %, 20 to 75 wt %, 20 to 70 wt %, 20 to 65 wt %, 20 to 60 wt %, 20 to 55 wt %, 20 to 50 wt %, 20 to 45 wt %, 20 to 40 wt %, 25 to 80 wt %, 25 to 75 wt %, 25 to 70 wt %, 25 to 65 wt %, 25 to 60 wt %, 33325 to 55 wt %, 25 to 50 wt %, 25 to 45 wt %, 25 to 40 wt %, 30 to 80 wt %, 30 to 75 wt %, 30 to 70 wt %, 30 to 65 wt %, 30 to 60 wt %, 30 to 55 wt %, 30 to 50 wt %, 30 to 45 wt %, 30 to 40 wt %, 35 to 80 wt %, 35 to 75 wt %, 35 to 70 wt %, 35 to 65 wt %, 35 to 60 wt %, 35 to 55 wt %, 35 to 50 wt %, 35 to 45 wt %, or 35 to 40 wt % of the CA staple fiber. In some cases, the first yarn may include from 75 to 100 wt %, 80 to 100 wt %, 90 to 100 wt %, or 95 to 100 wt % of the CA staple fiber.

The pilling-resistant fabric may comprise various amounts of the first and second yarns, so long as the first yarn comprising the CA staple fiber is present in sufficient quantities to reduce pilling compared to a fabric made without the CA staple fiber. Typically, the pilling-resistant fabric may comprise from 1 to 99, 5 to 95, 10 to 90, 15 to 85, 20 to 80, 25 to 75, 30 to 70, 35 to 65, 40 to 60, 45 to 55, or 50 wt % of the first yarn. The balance of the pilling-resistant fabric may comprise the second yard.

The second yarn may comprise one or more of the non-CA staple fibers described herein.

The pilling-resistant fabric according to the present disclosure, regardless of its mode of making, desirably has a higher pilling resistance rating than a fabric made without the CA staple fiber.

In some cases, the pilling-resistant fabric may have a pilling resistance rating of at least 0.5, at least 1, at least 1.5, at least 2, or at least 2.5 higher than the rating of a fabric made without the CA staple fiber measured according to ASTM D4970/D4970M-16e3 at 1000 rubs, at 2000 rubs, at 5000 rubs, and/or at 7000 rubs.

In some cases, the pilling-resistant fabric may have a pilling resistance rating of at least 4 or at least 4.5 according to ASTM D4970/D4970M-16e3 at 1000 rubs, at 2000 rubs, at 5000 rubs, and/or at 7000 rubs.

In some cases, the pilling-resistant fabric may have a pilling resistance rating of at least 0.5, at least 1, at least 1.5, or at least 2 higher than the rating of a fabric made without the CA staple fiber according to ASTM D3512/D3512M-2016 after 30 minutes and/or after 60 minutes.

In some cases, the pilling-resistant fabric may have a pilling resistance rating of at least 4 or at least 4.5 according to ASTM D3512/D3512M-2016 after 30 minutes and/or after 60 minutes.

In yet another aspect, the invention provides an article of manufacture comprising the pilling-resistant fabric. Examples of such articles include garments, window or seat coverings, or bedding.

Cellulose Acetate Staple Fibers

The CA staple fibers useful in the present disclosure can be formed from one or more kinds of cellulose acetate. For example, the cellulose acetate may be formed from cellulose diacetate, cellulose triacetate, or mixtures thereof. The cellulose acetate typically has a degree of substitution in the range of from 1.9 to 2.9. As used herein, the term “degree of substitution” or “DS” refers to the average number of acetyl substituents per anhydroglucose ring of the cellulose polymer where the maximum degree of substitution is 3.0.

In some cases, the cellulose acetate used to form the fibers may have an average DS of at least 1.95, at least 2.0, at least 2.05, at least 2.1, at least 2.15, at least 2.2, at least 2.25, or at least 2.3 and/or no more than 2.9, 2.85, 2.8, 2.75, 2.7, 2.65, 2.6, 2.55, 2.5, 2.45, 2.4, or 2.35, with greater than 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent of the cellulose acetate having a DS of greater than 2.15, 2.2, or 2.25. Desirably, greater than 90, greater than 95, greater than 98 wt %, or greater than 99 wt %, and up to 100 wt % of the total acyl substituents are acetyl substituents. Desirably, the cellulose acetate has no acyl substituents having a carbon number of greater than 2.

The cellulose acetate may have a weight-average molecular weight (Mw) of no more than 90,000, measured using gel permeation chromatography with N-methyl-2-pyrrolidone (NMP) as the solvent. In some cases, the cellulose acetate may have a Mw of at least 10,000, at least 20,000, at least 25,000, at least 30,000, at least 35,000, at least 40,000, or at least 45,000 and/or no more than 100,000, 95,000, 90,000, 85,000, 80,000, 75,000, 70,000, 65,000, 60,000, or 50,000.

The CA staple fiber may be formed by any suitable method. For example, the cellulose acetate may be formed by reacting a cellulosic material, such as wood pulp, with acetic anhydride and a catalyst in an acidic reaction medium to form a cellulose acetate flake. The flake may then be dissolved in a solvent, such as acetone or methyl ethyl ketone, to form a “solvent dope,” which can be filtered and sent through a spinnerette to form CA filament. In some cases, up to 1 wt % or more of titanium dioxide or other delusterant may be added to the dope prior to filtration, depending on the desired properties and ultimate end use of the fibers.

In some cases, the solvent dope or flake used to form the CA staple fibers may include few or no additives. Such additives can include, but are not limited to, plasticizers, antioxidants, thermal stabilizers, pro-oxidants, acid scavengers, inorganics, pigments, and colorants. In some cases, the CA staple fibers can include at least 90, at least 90.5, at least 91, at least 91.5, at least 92, at least 92.5, at least 93, at least 93.5, at least 94, at least 94.5, at least 95, at least 95.5, at least 96, at least 96.5, at least 97, at least 97.5, at least 98, at least 98.5, at least 99, at least 99.5, at least 99.9, at least 99.99, at least 99.995, or at least 99.999 wt % of cellulose acetate, based on the total weight of the fiber. Fibers formed according to the present disclosure may include no more than 10, 9.5, 9, 8.5, 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.5, 0.1, 0.01, 0.005, or 0.001 wt % of additives, including the specific additives listed herein.

At the spinnerette, the solvent dope can be extruded through a plurality of holes to form continuous cellulose acetate filaments. At the spinnerette, filaments may be drawn to form bundles of several hundred, or even thousand, individual filaments. For example, each of these bundles, or bands, may include at least 100, at least 150, at least 200, at least 250, at least 300, at least 350, or at least 400 and/or no more than 1000, no more than 900, no more than 850, no more than 800, no more than 750, or no more than 700 fibers. The spinnerette may be operated at any speed suitable to produce filaments and bundles having desired size and shape.

Multiple bundles may be assembled into a tow band, such as a crimped or an uncrimped tow band. The tow band may be of any suitable size and, in some instances, may have a total denier of at least 10,000 all the way up to 5,000,000.

The individual filaments, which are extruded in a generally longitudinally aligned manner and which ultimately form the tow band, are of a particular size. The linear denier per filament (weight in g of 9000 m fiber length), or DPF, of the CA filaments in the tow band and of the corresponding staple fibers in the yarn, are typically within a range of 0.5 to 4.0, 0.5 to less than 3, or from 1.0 to less than 3, measured according to ASTM D1577-01 using the FAVIMAT vibroscope procedure. In some cases, the DPF of the filaments, and of the corresponding staple fibers, may be within a range of 1.0 to 2.5, or 1.0 to 2.2, 1.0 to 2.1, 1.0 to 2.0, 1.0 to less than 2.0, 1.0 to 1.9, or 1.1 to 1.9. In yet other cases, the DPF of the filaments, and of the corresponding staple fibers, may be 0.5 to 3.5, 0.5 to 3.0, 0.5 to 2.3, 0.5 to 2.0, 0.5 to less than 2.0, 0.5 to 1.8, 0.9 to 4.0, 0.9 to 3.5, 0.9 to 3.0, 0.9 to 2.3, 0.9 to 2.0, 0.9 to less than 2.0, 0.9 to 1.8, 1.1 to 4.0, 1.1 to 3.5, 1.1 to 3.0, 1.1 to 2.3, 1.1 to 2, 1.1 to less than 2, or 1.1 to 1.8.

The individual filaments discharged from the spinnerette, and the corresponding staple fibers, can have a round or closed-C cross-sectional shape. In an acetone, solvent-spun process, the cross-section can be somewhat irregular or crenulated due to collapsing of the hardened surface. As used herein, the term “cross-section” refers to the transverse cross-section of the filament measured in a direction perpendicular to the direction of elongation of the filament. The cross-section of the filament may be determined and measured using Quantitative Image Analysis (QIA). The staple fibers may have a cross-section similar to the filaments from which they were formed.

The cross-sectional shape of an individual filament may be characterized according to its deviation from a round cross-sectional shape. In some cases, this deviation can be characterized by the shape factor of the filament, which is determined by the following formula:

Shape Factor=Perimeter/(4πCross-Sectional Area)^(1/2).

In some instances, the shape factor of the individual cellulose acetate filaments (or CA staple fiber) can be from 1 to 2, or 1 to 1.8, or 1 to 1.7, or 1 to 1.5, or 1 to 1.4, or 1 to 1.25, or 1 to 1.15, or 1 to 1.1. The shape factor of filament having a perfect round cross sectional shape is 1. The shape factor can be calculated from the cross-sectional area of a filament, which can be measured using QIA.

After multiple bundles are assembled into a tow band, it is passed through a crimping zone where a patterned wavelike shape is imparted to at least a portion, or substantially all, of the individual filaments. Imparting crimp is desirable to allow the staple fibers to be separated and oriented in the carding operation, and to provide a measure of cohesion to prevent a sliver from falling apart.

A suitable type of mechanical crimper is a “stuffing box” or “stuffer box” crimper, which uses a pair of nip rollers to force the tow band into the restriction of stuffer box just downstream of the rolls. The resulting compressive forces on the filaments cause the filaments to buckle, crimp, and interlock into a cohesive tow band. Examples of equipment suitable for imparting crimp to the filaments are described in, for example, U.S. Pat. Nos. 9,179,709; 2,346,258; 3,353,239; 3,571,870; 3,813,740; 4,004,330; 4,095,318; 5,025,538; 7,152,288; and 7,585,442. In some cases, the crimping step may be performed at a rate of at least 50 m/min (e.g., 75, 100, 125, 150, 175, 200, 225, 250 m/min) and/or no more than 750 m/min (e.g., 475, 450, 425, 400, 375, 350, 325, or 300 m/min).

Crimping may be performed such that the final staple fibers have a crimp frequency of at least 4, at least 5, least 7, at least 8, at least 9, at least 10, at least 12, and up to 30, up to 25, up to 20, or up to 19 crimps per inch (CPI), measured according to ASTM D3937. Desirably, the CA staple fibers have a crimp frequency of 4 to 24 CPI. In some cases, the CA staple fibers may have a crimp frequency of 5 to 20, 9 to 17, 9 to 14, or 12 to 17 CPI.

When crimped, the crimp amplitude of the fibers may vary and can, for example, be at least 0.85, at least 0.90, at least 0.93, at least 0.96, at least 0.98, at least 1.00, or at least 1.04 mm. Additionally, or in the alternative, the crimp amplitude of the fibers can be up to 1.75, up to 1.70, up to 1.65, up to 1.55, up to 1.35, up to 1.28, up to 1.24, up to 1.15, up to 1.10, up to 1.03, or up to 0.98 mm.

Additionally, the final CA staple fibers may have a crimp ratio of at least 1:1. As used herein, “crimp ratio” refers to the ratio of the non-crimped tow length to the crimped tow length. In some embodiments, the staple fibers may have a crimp ratio of at least 1:1, at least 1.1:1, at least 1.125:1, at least 1.15:1, or at least 1.2:1.

Crimp amplitude and crimp ratio are determined according to the following calculations, with the dimensions referenced being shown in the FIGURE:

Lc=1/crimp frequency

Crimp Ratio=L ₀ /Lc

where LC is the crimped length and L₀ is the straight length. The amplitude (A) is calculated geometrically, as shown in the FIGURE, using half of the straight length (L₀/2) and half of the crimped length (LC/2). The uncrimped length is simply measured using conventional methods.

After crimping, the fibers may be dried in a drying zone in order to reduce the moisture (total of water and solvent) content of the tow band. In some cases, the drying zone may be sufficient to reduce the final moisture content of the tow band to no more than 9, or less than 8.5, less than 8, less than 7.5, less than 7, less than 6.5, or less than 6 wt %, based on the total weight of the fiber or yarn. Typically, the moisture content does not drop below 3.5 wt % or below 4 wt %. Any suitable type of dryer can be used, such as a forced air oven, a drum dryer, or a heat setting channel. The dryer may be operated at any temperature and pressure conditions that provide the requisite level of drying without damaging the fiber or yarn.

Once dried, the tow band may be fed to a cutting zone, or optionally first baled and the resulting bales may be introduced into a cutting zone, where the elongated tow bands may be cut into staple fibers. The staple fibers of the present disclosure may be cut to a length that is dependent upon the application needs. The staple fiber length is generally in the range of at least 5 mm and up to 150 mm. Other examples of cut lengths include at least 10 mm, or at least 11 mm, and no more than 100mm, no more than 90 mm, no more than 80 mm, no more than 60 mm, no more than 55 mm, no more than 50 mm, no more than 45 mm, no more than 40 mm, no more than 38 mm, no more than 35 mm, no more than 32 mm, no more than 30 mm, no more than 28 mm, or no more than 26 mm. Examples of cut length ranges include 10 to 55 mm, 10 to 50 mm, 10 to 45 mm, 11 to 38 mm, or 11 to 26 mm. Other examples of CA staple fiber cut length ranges include 20 to 80 mm, 30 to 60 mm, 30 to 55 mm, and 34 to 51 mm.

Any cutting device that can cut the filaments to a desired length without excessively damaging the fibers may be used. Examples of cutting devices include, but are not limited to, rotary cutters, guillotines, stretch breaking devices, reciprocating blades, and combinations thereof. Once cut, the staple fibers may be baled or otherwise bagged or packaged for subsequent transportation, storage, and/or use.

During the CA staple fiber production process, one or more coatings or “finishes” may be applied to the filament and/or tow band. Typical finishes include those that modify the frictional or antistatic properties of the filaments and/or resulting fibers. In some cases, the staple fibers may include at least two finishes applied to all or a portion of the staple fiber surface in one step or in multiple steps, at one or more points, during the fiber production process. When two or more finishes are applied to the fibers, the finishes may be applied in one step as a blend of two or more different finishes, or the finishes may be applied separately at different steps/locations during the process. For example, in some cases, the staple fibers may be at least partially coated with a spinning or spin finish applied to the filaments at or between filament spinning and before crimping to facilitate the filament spinning and/or crimping steps described previously. The finish may be added to the fiber at the filament spinning step or between fiber spinning and gathering the filaments into a bundle. Alternatively, or in addition, the finish may be applied at any point at or after filament spinning and before the cutting step, and can be applied to individual filaments, bundles, or the tow band.

Any suitable method of applying the finish may be used and can include, for example, spraying, wick application, dipping, or use of squeeze, lick, or kiss rollers.

The cumulative amount of all finish applied will depend on the type of finishes, the fiber denier, the cut length, and the type of CA used. The finishes may be of any suitable type and can be present on the filaments, tow band, CA staple fibers, and/or spun yarn in an amount of at least 0.05%, at least 0.10%, at least 0.15%, at least 0.20%, at least 0.25%, at least 0.30%, at least 0.35%, at least 0.40%, at least 0.45%, at least 0.50%, at least 0.55%, or at least 0.60% finish-on-yarn (FOY) relative to the weight of the dried CA staple fiber. Alternatively, or in addition, the cumulative amount of finish may be present in an amount of no more than 4.0%, no more than 3.5%, no more than 3.0%, no more than 2.5%, no more than 2.0%, less than 2.0%, no more than 1.8%, no more than 1.5%, no more than 1.2%, no more than 1.0%, no more than 0.9%, no more than 0.8%, or no more than 0.7% FOY, based on the total weight of the dried CA staple fiber. The amount of finish on the fibers as expressed by weight percent may be determined by solvent extraction.

As used herein, “FOY” or “finish-on-yarn” refers to the amount of finish on the yarn less any added water, and in this context, yarn does not refer to spun yarn, but rather to the CA tow band that would be representative of and be the same amount on the CA staple fibers. As noted above, one or two or more types of finishes may be used. The cumulative amount of finish on the fibers can range from 0.10 to 1.0, 0.10 to 0.90, 0.10 to 0.80, 0.10 to 0.70, 0.15 to 1.0, 0.15 to 0.90, 0.15 to 0.80, 0.15 to 0.70, 0.20 to 1.0, 0.20 to 0.90, 0.20 to 0.80, 0.20 to 0.70, 0.25 to 1.0, 0.25 to 0.90, 0.25 to 0.80, 0.25 to 0.70, 0.30 to 1.0, 0.30 to 0.90, 0.30 to 0.80, or 0.30 to 0.70, each as % FOY.

If employed, the antistatic finish may be a cationic, a non-ionic, or an anionic finish and may be in the form of a solution, an emulsion, or a dispersion. The antistatic finish may be an aqueous emulsion, and it may or may not include any type of hydrocarbon, oil including silicone oil, waxes, alcohol, glycol, or siloxanes. The specific type of antistatic finish applied to the filaments or fibers may depend, at least in part, on the final application for which the staple fibers will be used. Examples of suitable antistatic finishes can include, but are not limited to, phosphate salts, sulfate salts, ammonium salts, and combinations thereof. Minor amounts of other components, such as surfactants, may also be present in order to enhance the stability and/or processability of the finish, and/or to make it more desirable for the intended end use of the fiber (e.g., non-irritating when the fiber may be in contacted with a user's skin). Further, depending on the end use of the CA staple fibers, the finish may be compliant with various Federal and state regulations and can be, for example, non-animal, Proposition 65 compliant, and/or FDA food contact approved.

The antistatic finish may impact the interaction of the coated fiber with water by modifying the hydrophilicity of the uncoated fiber to make it more hydrophilic. Using an antistatic finish may impart additional moisture to the fiber itself. In some instances, adding the antistatic finish can result in at least 0.05%, at least 0.1%, at least 0.15%, at least 0.20%, at least 0.30%, at least 0.50%, or at least 0.80%, and up to 1.5%, or up to 1.0% by weight of moisture added to the fiber.

The CA staple fibers can include little or no plasticizer and may exhibit enhanced biodegradability under industrial, home, and soil conditions, even as compared to CA staple fibers with higher levels of plasticizer.

In some cases, the CA staple fibers can include no more than 5, no more than 4.5, no more than 4, no more than 3.5, no more than 3, no more than 2.5, no more than 2, no more than 1.5, no more than 1, no more than 0.5, no more than 0.25, no more than 0.10, no more than 0.05, or no more than 0.01 wt % of plasticizers, based on the total weight of the fiber, or the fibers may include no added plasticizer. When present, the plasticizer may be incorporated into the fiber itself by being blended with the solvent dope or cellulose acetate flake, or the plasticizer may be applied to the surface of the fiber or filament by spraying, by centrifugal force from a rotating drum apparatus, or by an immersion bath.

Examples of plasticizers that may be present, or not present, in or on the fibers can include, but are not limited to, aromatic polycarboxylic acid esters, aliphatic polycarboxylic acid esters, lower fatty acid esters of polyhydric alcohols, and phosphoric acid esters. Additional examples include, but are not limited to, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, dimethoxyethyl phthalate, ethyl phthalylethyl glycolate, butyl phthalylbutyl glycolate, levulinic acid esters, dibutyrates of triethylene glycol, tetraethylene glycol, pentaethylene glycol, tetraoctyl pyromellitate, trioctyl trimellitate, dibutyl adipate, dioctyl adipate, dibutyl sebacate, dioctyl sebacate, diethyl azelate, dibutyl azelate, dioctyl azelate, glycerol, trimethylolpropane, pentaerythritol, sorbitol, glycerin triacetate (triacetin), diglycerin tetracetate, triethyl phosphate, tributyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, and tricresyl phosphate, and combinations thereof.

Additionally, the CA staple fibers of the present disclosure may not have undergone additional treatment steps designed to enhance the biodegradability of the fibers. For example, the fibers as described herein are desirably not hydrolyzed or treated with enzymes or microorganisms. The fibers may include no more than 1, no more than 0.75, no more than 0.5, no more than 0.25, no more than 0.1, no more than 0.05, or no more than 0.01 wt % of an adhesive, bonding agent, or other modifying agent. In some cases, the fibers may not include any adhesive, bonding, or modifying agent and may not be formed from any substituted or modified cellulose acetate. Modified cellulose acetate may include cellulose acetate that has been modified with a polar substituent, such as sulfates, phosphates, borates, carbonates, and combinations thereof.

In some cases, the CA staple fiber useful in the present disclosure is characterized by:

(i) a round or closed-C cross-sectional shape;

(ii) a cut length of 20 to 80 mm;

(iii) a crimp frequency of 4 to 24 crimps per inch (CPI); and

(iv) a denier per filament (DPF) of 0.5 to 4.0.

In additional cases, the CA staple fiber is characterized by:

(i) a round cross-sectional shape;

ii) a cut length of 34 to 51 mm;

(iii) a crimp frequency of 9 to 17 CPI; and

(iv) a DPF of 0.9 to 4.0.

In some cases, the CA staple fiber has a cut length of 30 to 60 mm, 30 to 55 mm, or 34 to 51 mm.

In some cases, the CA staple fiber has a crimp frequency of 5 to 20 CPI, 9 to 17 CPI, 9 to 14 CPI, or 12 to 17 CPI.

In some cases, the CA staple fiber has a DPF of 0.5 to 3.5, 0.5 to 3.0, 0.5 to 2.3, 0.5 to 2.0, 0.5 to less than 2.0, 0.5 to 1.8, 0.9 to 4.0, 0.9 to 3.5, 0.9 to 3.0, 0.9 to 2.3, 0.9 to 2.0, 0.9 to less than 2.0, 0.9 to 1.8, 1.1 to 4.0, 1.1 to 3.5, 1.1 to 3.0, 1.1 to 2.3, 1.1 to 2, 1.1 to less than 2, or 1.1 to 1.8.

In some cases, the blended yarn or the first yarn comprises 30 to 80 wt % of the CA staple fiber.

Fabrics

Fabrics made of spun yarns are widely used in a variety of applications. These fabrics are formed by weaving, knitting, crocheting, knotting, or felting yarn made of natural and/or synthetic materials, such as, for example, polyesters, polyamides, acrylics, polyurethanes, glass, wool, polypropylene, silk, cashmere, sisal, flax, hemp, cotton, a variety of regenerated cellulosic materials, such as viscose, modal, and lyocell, and is often formed as a blend of two or more of these materials. As noted above, yarns of one or more of these materials may be combined with the yarns containing the CA staple fibers according to the present disclosure to make pilling-resistant fabrics.

Alternatively, or in addition, non-CA staple fibers may be blended with the CA staple fibers to form yarns and subsequently to form pilling-resistant fabrics. Such non-CA staple fibers can include natural and/or synthetic fibers including, but not limited to, cotton; rayon including viscose or other types of regenerated cellulose such as cupro, tencel, modal, and lyocell; acetates such as polyvinylacetate; wool; polyamides including nylon; polyesters such as polyethylene terephthalate (PET), polycyclohexylenedimethylene terephthalate (PCT) and other copolymers; olefinic polymers such as polypropylene and polyethylene; acrylics; and combinations thereof.

In some cases, the pilling-resistant fabrics are formed by weaving or knitting.

Examples of suitable types of textile fabrics formable from the yarns containing CA staple fibers can include, but are not limited to, garments/clothing (undergarments, socks, hats, shirts, pants, dresses, coats, scarves, gloves, etc.), bags, baskets, upholstered furnishings, window shades, towels, table cloths, bed coverings, flat surface coverings, in art work, filters, flags, backpacks, tents, handkerchiefs, rags, balloons, kites, sails, parachutes, automotive upholstery, protective clothing such as against heat for firefighters and welders, protective clothing for bullet armor or stab protection, medical textile fabrics such as implants, and agrotextile fabrics for crop protection.

To remove any doubt, the present invention includes and expressly contemplates and discloses any and all combinations of embodiments, features, characteristics, parameters, and/or ranges mentioned herein. That is, the subject matter of the present invention may be defined by any combination of embodiments, features, characteristics, parameters, and/or ranges mentioned herein.

It is contemplated that any ingredient, component, or step that is not specifically named or identified as part of the present invention may be explicitly excluded.

Any process/method, apparatus, compound, composition, embodiment, or component of the present invention may be modified by the transitional terms “comprising,” “consisting essentially of,” or “consisting of,” or variations of those terms.

As used herein, the indefinite articles “a” and “an” mean one or more, unless the context clearly suggests otherwise. Similarly, the singular form of nouns includes their plural form, and vice versa, unless the context clearly suggests otherwise.

While attempts have been made to be precise, the numerical values and ranges described herein should be considered as approximations, unless the context indicates otherwise. These values and ranges may vary from their stated numbers depending upon the desired properties sought to be obtained by the present disclosure as well as the variations resulting from the standard deviation found in the measuring techniques. Moreover, the ranges described herein are intended and specifically contemplated to include all sub-ranges and values within the stated ranges. For example, a range of 50 to 100 is intended to include all values within the range including sub-ranges such as 60 to 90, 70 to 80, etc.

Any two numbers of the same property or parameter reported in the working examples may define a range. Those numbers may be rounded off to the nearest thousandth, hundredth, tenth, whole number, ten, hundred, or thousand to define the range.

The content of all documents cited herein, including patents as well as non-patent literature, is hereby incorporated by reference in their entirety. To the extent that any incorporated subject matter contradicts with any disclosure herein, the disclosure herein shall take precedence over the incorporated content.

This invention can be further illustrated by the following working examples, although it should be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention.

EXAMPLES Analytical Methods

Fiber analysis was conducted according to AATCC TM20A-2014.

Pilling resistance according to ASTM D4970/D4970M-16e3 (Martindale Abrasion Tester, No Additional Weight Added) was determined at 1000, 2000, 5000, and/or 7000 rubs.

Pilling resistance according to ASTM D3512/D3512M-2016 (Random Tumbler) was determined after 30 minutes and after 60 minutes.

Examples 1-38

Pilling testing was conducted on a variety of CA staple fiber blended fabrics made in different fabric constructions and by different mills.

The CA staple fiber used in the testing had a round cross-sectional shape, a DPF of 1.8, a cut length of 38 mm, and a crimp frequency of 17 CPI.

Single jersey knit fabrics were made with the CA staple fibers in different blend combinations with non-CA staple fibers. These fabrics were made by three different mills: Mill 1; Mill 2; and Mill 3.

2/1 Twill woven fabrics were made with the CA staple fibers in different blend combinations with non-CA staple fibers. These fabrics were made by a fourth mill: Mill 4.

The pilling resistance ratings of the single jersey knit fabrics from Mill 1 are reported in Table 1.

TABLE 1 Single Jersey Knit Fabrics from Mill 1 Martindale Pilling Resistance Rating Example No. Fabric Composition (wt %) 2000 Rubs 7000 Rubs 1 100% Cotton 2 1.5 2 60-65% Cotton/35-40% CA 3 2.5 3 100% Lyocell 2.5 1.5 4 60-65% Lyocell/35-40% CA 3 3 5 100% Modal 3 2 6 60-65% Modal/35-40% CA 3, 3.5 2.5, 2.5 7 100% Polyester n/t n/t 8 60-65% Polyester/35-40% CA 3 2.5 n/t = not tested

The pilling resistance ratings of the single jersey knit fabrics from Mill 2 are reported in Table 2.

TABLE 2 Single Jersey Knit Fabrics from Mill 2 Martindale Pilling Resistance Rating Example No. Fabric Composition (wt %) 2000 Rubs 7000 Rubs 9 100% Cotton 4.5 4 10 60-65% Cotton/35-40% CA 2.5 2 11 100% Lyocell 3.5 3 12 60-65% Lyocell/35-40% CA 4 4 13 95% Modal/5% Elastane 3 2.5 14 60-65% Modal/35-40% CA 3.5, 4 3.5, 4 15 100% Polyester 3.5 3 16 60-65% Polyester/35-40% CA 4 3.5 17 100% Viscose 3 2.5 18 60-65% Viscose/35-40% CA 3.5 3

The pilling resistance ratings of the twill woven fabrics from Mill 4 are reported in Table 3.

TABLE 3 Twill Woven Fabrics from Mill 4 Martindale Pilling Resistance Rating Example No. Fabric Composition (wt %) 2000 Rubs 7000 Rubs 19 100% Cotton 4.5 4.5 20 60-65% Cotton/35-40% CA 3.5 3 21 100% Lyocell 3.5 4.5 22 60-65% Lyocell/35-40% CA 4.5 4.5 23 95% Modal/5% Elastane 3 2.5 24 60-65% Modal/35-40% CA 4.5 4.5 25 100% Polyester 3 2.5 26 60-65% Polyester/35-40% CA 3 2.5 27 100% Viscose 3 2.5 28 60-65% Viscose/35-40% CA 4 3.5

The fiber analysis and pilling resistance ratings of the single jersey knit fabrics from Mill 3 are reported in Table 4.

TABLE 4 Single Jersey Knit Fabrics from Mill 3 Pilling Resistance Rating Pilling Resistance Rating Fiber (ASTM D4970/D4970M - 16e3) (ASTM D3512/D3512M - 2016) Example Analysis 1000 2000 5000 7000 After After No. (% wt) Rubs Rubs Rubs Rubs 30 mins. 60 mins. 29 94.6% Modal 1.5 1.5 1.5 1.5 4 4 5.4% Spandex 30 59.2% Modal 1.5 2 2 2.5 4.5 4.5 35.1% CA 5.7% Spandex 31 95.1% Cotton 1 1 1 1 3.5 3.5 4.9% Spandex 32 57.6% Cotton 2 2 1.5 1.5 4 4 36.1% CA 6.3% Spandex 33 94.3% Lyocell 2 2 3 44 4.5 4.5 5.7 - Spandex 34 67.1% Lycocell 4 4.5 4.5 4.5 4.5 4.5 26.7% CA 6.2% Spandex 35 94.6% Polyester 2 1.5 1 1 3.5 2 5.4% Spandex 36 58.4% Polyester 2.5 2 1.5 1.5 3 2.5 35.9% CA 5.7% Spandex 37 94.6% Viscose 1.5 1.5 1 1 2 2 5.4% Spandex 38 59.4% Viscose 1.5 1.5 1.5 1.5 4 4 34.7% CA 5.9% Spandex

The invention has been described in detail with particular reference to specific embodiments thereof, but it will be understood that variations and modifications can be made within the spirit and scope of the invention. 

1. A method of making a pilling-resistant fabric, the method comprising: (a) blending a cellulose acetate (CA) staple fiber with a non-CA staple fiber to form a blended yarn comprising 20 to 80 wt % of the CA staple fiber, based on the total weight of the blended yarn; and (b) forming a pilling-resistant fabric comprising the blended yarn; wherein the pilling-resistant fabric has a higher pilling resistance rating than a fabric made without the CA staple fiber; and wherein the CA staple fiber has: (i) a round or closed-C cross-sectional shape; (ii) a cut length of 20 to 80 mm; (iii) a crimp frequency of 4 to 24 crimps per inch (CPI); and (iv) a denier per filament (DPF) of 0.5 to 4.0.
 2. A method of making a pilling-resistant fabric, the method comprising: (a) providing a first yarn comprising at least 20 wt % of a cellulose acetate (CA) staple fiber, based on the total weight of the first yarn; and (b) forming a pilling-resistant fabric comprising the first yarn and a second yarn comprising a non-CA staple fiber; wherein the pilling-resistant fabric has a higher pilling resistance rating than a fabric made without the CA staple fiber; and wherein the CA staple fiber has: (i) a round or closed-C cross-sectional shape; (ii) a cut length of 20 to 80 mm; (iii) a crimp frequency of 4 to 24 crimps per inch (CPI); and (iv) a denier per filament (DPF) of 0.5 to 4.0.
 3. (canceled)
 4. (canceled)
 5. The method according to claim 1, wherein the blended yarn or the first yarn comprises 20 to 75 wt % of the CA staple fiber.
 6. The method according to claim 1, wherein the first yarn comprises from 75 to 100 wt % of the CA staple fiber.
 7. The method according to claim 1, wherein the pilling-resistant fabric comprises at least 10 wt %, of the blended yarn.
 8. The method according to claim 1, wherein the non-CA staple fiber comprises nylon, wool, silk, acrylic, bamboo, linen, hemp, cotton, lyocell, modal, polyester, viscose, spandex, or combinations thereof.
 9. The method according to claim 1, wherein the CA staple fiber has a cut length of 30 to 60 mm.
 10. The method according to claim 1, wherein the CA staple fiber has a crimp frequency of 5 to 20 CPI.
 11. The method according to claim 1, wherein the CA staple fiber has a DPF of 0.5 to 2.3.
 12. The method according to claim 1, wherein the blended yarn or the first yarn comprises 30 to 80 wt % of the CA staple fiber, and wherein the CA staple fiber has: (i) a round cross-sectional shape; (ii) a cut length of 34 to 51 mm; (iii) a crimp frequency of 9 to 17 CPI; and (iv) a DPF of 0.9 to 4.0.
 13. The method according to claim 1, wherein step (b) comprises weaving or knitting.
 14. The method according to claim 1, wherein the pilling-resistant fabric has a pilling resistance rating of at least 0.5 higher than the rating of a fabric made without the CA staple fiber measured according to ASTM D4970/D4970M-16e3 at 1000 rubs.
 15. The method according to claim 1, wherein the pilling-resistant fabric has a pilling resistance rating of at least 4 according to ASTM D4970/D4970M-16e3 at 1000 rubs.
 16. The method according to claim 1, wherein the pilling-resistant fabric has a pilling resistance rating of at least 0.5 higher than the rating of a fabric made without the CA staple fiber according to ASTM D3512/D3512M-2016 after 30 minutes.
 17. The method according to claim 1, wherein the pilling-resistant fabric has a pilling resistance rating of at least 4 according to ASTM D3512/D3512M-2016 after 30 minutes.
 18. (canceled)
 19. (canceled)
 20. (canceled) 